The present invention is related to a scanning apparatus. In spite of the rapid and almost complete developement of the scanner products and the related technology, so far, the scanned targets to be scanned by the conventional scanners are still limited to those pictures or characters with white background. For some kinds of scanned targets with one or more background colors having low reflection degree, it is difficult to obtain a high efficiency and high resolution image. Thereby, the application of the scanner will be limited.